Meta-analysis of ACE gene I/D polymorphism and bipolar disorder susceptibility

Abstract

Background: A number of studies have been conducted to explore the association between ACE gene insertion/deletion (I/D) polymorphism and bipolar disorder (BPD). However, the reported results were conflicting. Aims: The aim of our study was to find evidence on whether ACE gene I/D polymorphism is associated with BPD using a meta-analysis. Methods: Data were collected from the following electronic databases: Pubmed, Elsevier Science Direct, Cochrane Library, CBM, CNKI and Wanfang. Meta-analysis was performed for genotypes ID vs. II, DD vs. II, DD vs. ID + II, ID + DD vs. II, and D allele vs. I allele in a fixed/random effect model. Results: Seven studies that included data from 605 cases and 1541 controls were identified. When all groups were pooled, we did not detect the association of ACE gene I/D polymorphism with BPD (P > 0.05). In the subgroup analysis, we did not detect the association of ACE gene I/D polymorphism with BPD in Caucasians (P > 0.05). An association of ACE gene I/D polymorphism with BPD was found in Asians for the contrast of DD vs. ID + II (OR = 2.01, 95% CI 1.08–3.74, P = 0.03), but not for other contrasts (P > 0.05). Conclusions: This meta-analysis suggests that there may be an association of ACE gene I/D polymorphism with BPD in Asians. Further studies are still needed in Asians.

• ACE
• Bipolar disorder
• Genetic polymorphism
• Meta-analysis

Acknowledgements

We thank all the people who give the help for this study. Especially, we have got the kind help from Dr. Thomas C. Baghai (Department of Psychiatry and Psychotherapy, Ludwig-Maximilian-University of Munich, Nussbaumstrasse 7, D-80336 Munich, Germany) and Dr. J. Mendlewicz (Department of Psychiatry, University Clinics of Brussels, Erasme Hospital, Free University of Brussels, 88 route de Lennik, 1070 Brussels, Belgium). This work was supported by grants from the National Natural Science Foundation of China (81001283).

Declaration of interest: The author reports no conflicts of interest. The author alone is responsible for the content and writing of the paper.